Territorial characteristics of low frequency electrostatic fluctuations in a simple magnetized torus

Kaur, Rajwinder; Singh, Ajay Kumar; Singh, Raghvendra; Sree, A. Sarada; Mattoo, S. K.

doi:10.1063/1.3551514

Cited by 9 publications

(16 citation statements)

References 35 publications

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“…The experimental apparatus BETA device (Figure 1) consists of a toroidal vacuum chamber of major radius 45 cm and minor radius 15 cm pumped down to base pressure of 10 −6 Torr [9][10][11]. A toroidal magnetic field is produced by a set of 16 coils and can be varied up to 1 kG.…”

Section: Methodsmentioning

confidence: 99%

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Self Consistently Generated Charge Cylinder in BETA Device

Kaur¹,

Sree²,

Mattoo³

2012

JMP

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This paper presents a study on near cathode space charge region in BETA (Basic Experiments in Toroidal Assembly), a toroidal plasma device with purely toroidal magnetic field. A charge cylinder has been found to be embedded in the plasma center corresponding to the hot filament cathode location in poloidal cross section. This charge cylinder has been created by the primary electrons emitted from the filament surface, which in turn, leads to the formation of a potential well in the core plasma. We have proposed a model, which shows that a tiny fraction of injected energetic electrons is sufficient to sustain the observed potential well. We have examined the equilibrium of the charge cylinder in poloidal cross-section and found that it exhibits equilibrium configuration by forming circulation pattern of primary electrons. The circulation pattern is formed by vertical drift due to toroidal magnetic field and self-consistent poloidal <i>E×B</i> drift. We have concluded that the self-consistency is in adjusting the poloidal drift to the vertical drift of the trapped primary electrons

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Section: Methodsmentioning

confidence: 99%

“…This paper presents an experimental study on near cathode space charge region in a hot filament cathode discharge produced toroidal plasma device BETA. The plasma in BETA device [9][10][11] is produced by a hot filament cathode discharge. The hot filament cathode injects energetic primary electrons into the plasma.…”

Section: Introductionmentioning

confidence: 99%

Self Consistently Generated Charge Cylinder in BETA Device

Kaur¹,

Sree²,

Mattoo³

2012

JMP

Self Cite

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“…(8); the conditional spectrum is estimated using Eq. (10). The average poloidal wave number k h is estimated using Eq.…”

Section: A Linear Spectral Analysismentioning

confidence: 99%

“…9 In another set of experiments in BETA, with toroidal field set at one value, characterization of different regions with suitable instabilities has been done. 10 More recently, the role of fluctuations in driving the poloidal flow and achieving an "effective rotational transform" at a fixed magnetic fields has been elucidated, [11][12][13] though a magnetic rotational transform as in tokamaks does not exist in this device. A clear flowfluctuation connection and plasma filling in the entire radial domain has been demonstrated.…”

Section: Introductionmentioning

confidence: 99%

Coherent to turbulence transition, enhanced flow and confinement in a simple toroidal plasma

et al. 2012

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In a simple toroidal plasma, self consistent poloidal flow generation at different toroidal fields is observed. On changing the magnitude of toroidal field, transition occurs in the nature of fluctuation from highly coherent modes at low magnetic field to a turbulent broadband spectrum at high field accompanied by significant improvement in the confinement. Interestingly, though the coherence is reduced with the increasing field, the fluctuation driven poloidal flux remains comparable. The observed increase in the densities on high field side with the increase in magnetic field is simultaneously accompanied by the enhanced net poloidal flow. The present work demonstrates that in a toroidal compressible plasma, an intimate relationship exists between the fluctuations, self consistently generated flows and enhanced confinement. V C 2012 American Institute of Physics.

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“…Low beta plasma embedded in a pure toroidal magnetic field is susceptible to different types of flute type instabilities [23][24] with frequency below the ion gyro frequency, namely the velocity-shear instability driven by non-uniform electric field; the Rayleigh-Taylor (R-T) instability arising from an unfavorable curvature in the magnetic field with density gradient antiparallel to it; and the gradient-drift instability that arises due to relative drift between the electrons and ions. Coherent low-frequency fluctuations are excited spontaneously at 0.02 T. The low-frequency mode is identified as due to curvature-induced R-T instability favored by velocity shear.…”

Section: Toroidal Plasma Experiments In Betamentioning

confidence: 99%

From Electrojet to ITER: India's Journey in Experimental Plasma Physics

John¹

2017

ujpa

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India has an international presence in PlasmaPhysics and its diverse applications such as thermonuclear fusion, material processing, strategic and environmental applications and plasma devices. From a modest start in the early 1970s, we have made great strides in the field of experimental plasma physics. Capacity building in techniques relevant to plasma production, manipulation and parameter control, pulsed power, creation of magnetic fields of complex geometries, clean vacuum and pumping systems, development and deployment of diagnostics to enable understanding of fundamental processes in plasmas and computer simulation to model plasma phenomena have been truly remarkable. Parallel to this, a community of physicists, engineers and computer experts has grown and matured. Funding mechanisms and financial support essential to broad base the research and development activity by drawing in Universities and education institutes have been nucleated. It is through these activities that the human resource and technology development essential to sustain India's ambitious forays into magnetic confinement fusion and industrial and strategic plasma applications has taken place.

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Territorial characteristics of low frequency electrostatic fluctuations in a simple magnetized torus

Cited by 9 publications

References 35 publications

Self Consistently Generated Charge Cylinder in BETA Device

Self Consistently Generated Charge Cylinder in BETA Device

Coherent to turbulence transition, enhanced flow and confinement in a simple toroidal plasma

From Electrojet to ITER: India's Journey in Experimental Plasma Physics

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